1. Field of the Invention
The present invention generally relates to an operation of a ballast. The present invention specifically relates to ground fault detectors on the input side of a ballast.
2. Description of the Related Art
Currently, an isolated safety circuit on the output side of a ballast are employed to protect a person from shock when installing lamps. For example, U.S. Pat. No. 4,563,719, U.S. Pat. No. 4,663,571, and U.S. Pat. No. 4,855,860 are all directed toward an isolated safety circuit on the output side of a ballast. However, a drawback to this mode of protection is the sensitivity of the circuit to potential shock as related to an activation threshold that may still result in an uncomfortable electric sting being felt by the person of a non-isolated ballast. The present invention is an improvement over the prior art.
The present invention is a ballast safety circuit. Various aspects of the present invention are novel, non-obvious, and provide various advantages. While the actual nature of the present invention covered herein can only be determined with reference to the claims appended hereto, certain features, which are characteristic of the embodiments disclosed herein, are described briefly as follows.
One form of the present invention is a device comprising a ballast and a ballast safety circuit. The ballast has a first input line and a second input line. The ballast safety circuit is in electrical communication with the first input line and the second input line where the ballast safety circuit is operable to detect an occurrence of a leakage current flowing through the second input line when a person is attempting to a mount a lamp on the ballast. In one embodiment, the ballast safety circuit includes a magnetic core, a first coil winding wound around the magnetic core, a second coil winding wound around the magnetic core, and a third coil winding wound around the magnetic core. The first coil winding is in electric communication with the first input line. The second coil winding is in electric communication with a second input line of the ballast. The third coil winding is operable to detect the leakage current flowing through the second input line.
The foregoing form as well as other forms, features and advantages of the present invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the present invention rather than limiting, the scope of the present invention being defined by the appended claims and equivalents thereof.